AS THE IOWA caucuses and the primaries that follow get closer, the current crop of presidential candidates is under growing pressure to explain how they propose to get the nation's finances back in order.

To find out what they have in mind on taxes, Citizens for Tax Justice (an advocacy group that has long pushed for a more progressive tax system) sent questionnaires to all the candidates. Except for Alexander Haig and Pat Robertson, each of the candidates replied in one way or another. Drawing from their responses to the CTJ questionnaire and their public statements, here, in alphabetical order and starting with Democrats, is what we found:

Democrats: Bruce Babbitt

The former Arizona governor deserves credit for stating what many other candidates believe but are afraid to say: increased taxes will be needed to bring down the deficit. But Babbitt is generally against relying on progressive income tax hikes, even on the wealthiest people, arguing that "it would be wrong to break faith with last year's tax reform." Instead, with what he calls a "Progressive National Consumption Tax" -- a five percent national sales tax -- the former Arizona governor believes he can knock $40 to $50 billion a year off the deficit.

Because those with lower incomes spend a greater share of their earnings, every sales tax ever enacted has been regressive -- even if food, housing and other necessities are exempted, average families would pay three times as much of their income in sales taxes as wealthy people and poor people five times as much. But Babbitt insists his tax would be fair because, in addition to exempting necessities, he would provide income tax credits, larger standard deductions or direct rebates for the less well-off. "It would be simple and fair," he asserts, "with no loopholes and no special breaks."

But most poor people couldn't benefit from credits because they don't file federal income tax returns and Babbitt's direct rebate plan would be an administrative quagmire. In any event, he offers no solution to the heavy taxes his plan would impose on middle-income families compared to the rich.

Oddly, Babbitt opposes excise taxes because they're regressive. He is also against a tax on imported oil because, he says, it goes against the principle of open international markets. And he does, in fact, offer a few income tax proposals: limiting mortgage interest deductions to $20,000 a year; ending mortgage deductions on second homes, and fully taxing social security benefits (which currently are partially taxed in the case of better-off retirees). He also favors user fees for certain federal services.

Michael Dukakis

The Massachusetts governor opposes Babbitt's call for a national sales tax, labeling it regressive, and he's firmly against the tariff on imported oil advocated by several other candidates, calling it "a terrible mistake" that could cost "half a million jobs." He also has expressed a "disinclination to make rapid changes in the {income} tax system" because of the need for "some stability and predictability."

Nevertheless, with little to offer in the way of spending reduction proposals, Dukakis admits that "no serious candidate can rule out a revenue increase." So, where does he think we should look? "Before we rush to impose any new taxes on the American public," he says, "the federal government should first implement a tough national policy of revenue enforcement." Few will disagree in principle -- who doesn't want to crack down on tax cheats? -- and Dukakis has had some success in improving tax enforcement as Governor of Massachusetts. But his contention that up to $100 billion in federal taxes now is being evaded is hard to credit if only because reporting of wages on tax returns is already close to 100 percent (thanks to withholding). To buy his arithmetic you would have to believe that more than half the taxes legally due on profits, dividends, interest and so forth now go uncollected.

Richard Gephardt

Gephardt first gained national attention when he lent his name to the Bradley-Gephardt "Fair Tax" plan, which became the model for the tax reform act of 1986. For raising additional revenue, Gephardt, like so many other Democratic candidates, says that increased income tax rates "should only be used to raise revenue as a last resort." Instead, Gephardt says he wants to continue closing loopholes that the 1986 bill left open, such as scaling back accelerated depreciation, stopping the decline in estate taxes, curbing incentives for tax-shelter farming, and ending tax breaks for companies that move plants overseas. He also favors increasing the minimum corporate tax, along with improved enforcement and user fees for federal services.

Gephardt opposes a national sales tax, and sponsored a congressional resolution against increased excise taxes but "doesn't rule anything out." He favors a $5 a barrel fee on imported oil, claiming it would encourage energy conservation, but his claim that it would raise $50 billion over three years seems wildly inflated given likely exemptions for home heating oil and imports from friendly nations. In any event, the proceeds would not go toward reducing the deficit. Instead, the funds would be used to pay for new education and training programs.

Albert Gore Jr.

"Taxes should be considered only as a last resort," Gore says frequently, echoing so many other candidates. He rejects Babbitt's national sales tax plan, and has expressed opposition to consumption taxes in general. On the subject of a tariff on imported oil, he is uncommitted. "Energy is a national problem deserving of a national response," and so he might support such a tax if "circumstances warranted."

Lately, Gore has mentioned that if higher taxes are needed, they ought to fall on those most able to pay. Specifically, his "last resort" taxes include a five-percent tax on "luxury items that cost more than $30,000"; raising the corporate tax rate back to 40 percent; taxing capital gains on inherited property (they're now exempt); and imposing additional taxes on Social Security benefits for upper-income retirees. Many of Gore's recent tax ideas seem reasonable enough, but he'll need to keep expanding his list.

Gary Hart

Hart wasn't included in our survey because he wasn't running at the time we conducted it. Back in the race, however, he offers one of the most comprehensive proposals to cut the deficit. Hart repeats his long-standing support for a $10 a barrel oil import fee (which Colorado oil producers favor) and, like Gore, he favors additional "luxury taxes." He calls for increased income taxes on better-off Social Security recipients and $50 billion in higher taxes on tobacco and alcohol over five years. Finally, Hart wants higher income taxes on businesses and people making more than $200,000. Some of these "new ideas" wouldn't raise much money and others would be tough on the poor. Still, unlike the plans of most other candidates, Hart's program at least adds up.

Jesse Jackson

Jackson has harshly criticized the Reagan tax cuts of 1981, calling them "a reverse Robin Hood process, taking from the poor and giving to the rich." Arguing that wealthy individuals and corporations are "not paying their fair share," he favors restoring a top tax rate of 50 percent on the richest taxpayers -- or at a minimum, repealing this year's further drop in the top rate from 38.5 to 28 percent. Jackson also rejects the economic theory of last year's tax reform act, which attempted to reduce government involvement in business and investment decisionmaking. Instead, he would return to a more active role for the tax code in stimulating private-sector activities. He would restore the investment tax credit and favorable treatment for capital gains (but try to target them to "productive" investments), keep the largest remaining corporate loophole -- accelerated depreciation -- and add new incentives for research and development. On the other hand, Jackson would repeal certain tax subsidies -- for defense contractors, tax-shelter farming and moving plants overseas -- that he regards as counter-productive.

Jackson's activist tax policy might also include a temporary excise tax on imported oil meant to save oil industry jobs and secure domestic energy sources, the revenues to be used for repairs of bridges and roads. Overall, Jackson's high-rate, targeted-incentives approach might not raise much revenue to reduce the deficit, and could lead to new horror stories about corporate and upper-income tax avoidance.

Paul Simon

Like Jackson, Simon is of two minds about taxes. The Illinois senator boasts about his vote against the loophole-closing 1986 tax reform act, and then professes that he wants to close even more loopholes. He complains that the revenues from tax reform were used to cut tax rates rather than reduce the deficit, and then proposes to reinstate the most costly corporate tax break that the reform bill eliminated.

To rectify the defects he sees in the 1986 tax reform, Simon would raise the top income tax rate on the rich -- perhaps back to last year's 38.5 percent -- and increase the top corporate rate to at least 35 percent. He favors closing loopholes like the special tax accounting rules for defense contractors, write-offs for business meals and entertainment and accelerated depreciation. "We should target all tax breaks so that the middle and low income earners get most of the benefit."

On the other hand, Simon wants to expand tax credits for research and development and provide tax deductions for interest on student loans. He also believes the investment tax credit -- a $40 billion a year corporate tax break should be reinstated, although his aides now say that Simon might want to "target" the credit to reduce its cost. Simon endorses increased excise taxes on telephone service, tobacco, beer and wine, a tariff on imported oil and a 6-cent a gallon increase in the gasoline tax along with higher user fees for certain federal services.

Republicans: George Bush

The Republican vice president declined to answer our questionnaire on the ground that he wanted to run a "issue-oriented campaign." The public record, however, shows that the man who once called supply-side theory "voodoo economics" is now a major practitioner. In order to increase revenues, Bush has called for another tax cut! He would reintroduce, and cap at 15 percent, the lower tax rate on capital gains from selling real estate, stocks, collectibles and other "capital assets." (Never mind that back in 1978 a cut in the top capital gains rate from 28 percent to 20 percent led to a boom in tax shelters designed to convert regular income into lightly-taxed capital gains. As a result, there were more capital gains reported to the IRS, but overall revenues went down, not up.) Virtually all of the tax benefits from Bush's proposal would go to the top 5 percent of the population.

Bob Dole

As chairman of the Senate Finance Committee, Dole shepherded President Reagan's huge 1981 tax cut through the Senate. Since then, he has been doing penance for that effort, playing a lead role in the 1982 scale-back of some of the more egregious 1981 breaks and the 1984 reform measure. As Senate majority leader Dole initially was skeptical about comprehensive tax reform, but ultimately played a key supporting role in passing the 1986 tax reform as well.

Currently, Dole admits that added revenues may be needed, and points to further loophole closing as the obvious first choice. Despite his sponsorship of a Senate-passed resolution this year to preserve the income-tax rate cuts provided by the 1986 reform act, Dole's unwillingness to rule out closing tax loopholes has been heavily criticized by some of the other Republican candidates, particularly borrow-and-spend conservatives Jack Kemp and Pierre du Pont.

For his part, Dole is equally contemptuous of the supply siders. "I have some bad news and some good news," he opened a speech to a business group a few years ago. "The good news is that a busload of supply-side economists just went over a cliff. The bad news is that there were two empty seats."

Pierre S. du Pont IV

Controlling the deficit is far less important to the former Delaware governor -- a supply-sider's supply-sider -- than preventing any tax hikes. Although du Pont would cut farm subsidies and welfare, some of his plans, such as new big tax incentives for retirement saving, would be very costly. He boasts that he was the first candidate to take the "Taxpayer Protection Pledge" to oppose any increase in taxes and he has challenged all the other candidates to do the same.

Alexander Haig

Haig has criticized what he calls the Reagan administration's fiscal flabbery" and asserted that reducing the deficit is the "first step toward greater prosperity." Until recently, in calling for Congress and the president to strike a "grand compromise" on attacking the national debt, Haig was ready to put taxes on the table. "No, I would not rule out a tax increase," he boldly asserted, although he was silent on what kinds of tax increases he might favor.

But after the stock crash, Haig switched to opposing higher taxes as potentially detrimental to the economy. Now he calls for new tax incentives for business investment.

Jack Kemp

Kemp proudly takes credit for the 1981 tax cuts that played such a key role in creating the deficit crisis, and boasts that he hasn't voted for a tax increase in his 17 years in Congress. "I think we can renew prosperity without inflation and raising taxes and cutting services," The answer? More supply-side tax cuts and a return to the gold standard.

Kemp gained some credit for the passage of the 1986 tax reform act, largely on the strength of so-called "tax reform" plan he introduced with Senator Robert Kasten. While Kemp and Kasten called for lower tax rates, however, they proposed no significant cutbacks in loopholes. Thus, far from being tax reform, the bill was simply another Kemp tax cut proposal. Kemp's antagonism to loophole-closing measures was further illustrated when he led Republican opposition to the House Ways and Means Committee's version of the tax reform act of 1986 -- opposition that almost led to the bill's demise.

More recently, Kemp has said that he would like to "get rid of that 28 percent rate" in the new tax law "and have just one rate at 18 or 20 percent." Since the bottom tax rate is now 15 percent, this would in fact mean a 33 percent tax increase for most American families.

Pat Robertson

Robertson has remarked that deficits are "fiscally and morally wrong," but he opposes new taxes "of any kind" (except, perhaps, for higher excise taxes on alcohol and cigarettes). He's a supporter of a flat-rate tax but is big on costly tax incentives. He's also said he wants to expand the personal exemption. So how does he plan to get rid of immoral deficits without any new revenues?

Besides banalities about eliminating waste and mismanagement in government, including turning many government programs over to the private sector, Robertson offers an unusual suggestion: banning abortion, he says, would produce more taxpayers, and therefore more revenue, without any change in the tax code.

Robert S. McIntyre is director and Jonathan M. Crystal is a policy analyst for Citizens for Tax Justice which played a key role in the 1986 tax reform measure.